Improved talloc.c

[andreas moroder]

I found two errors so I send the new version of my diff against 2.2.1.a

--- talloc.c	Sat Aug 25 14:39:18 2001
+++ talloc.new	Sat Aug 25 14:41:27 2001
@@ -1,4 +1,4 @@
-/*
+/*
    Unix SMB/Netbios implementation.
    Version 3.0
    Samba temporary memory allocation functions
@@ -35,10 +35,20 @@

 #include "includes.h"

+// If there are systems that must allign on a bigger boundary then  8
+// the constant 3 must be changed
+
+#define TALLOC_NEW_ALLIGN	8
+
+static unsigned short tc_offset;
+
+
+
 /* initialise talloc context. */
 TALLOC_CTX *talloc_init(void)
 {
 	TALLOC_CTX *t;
+	short l;
 
 	t = (TALLOC_CTX *)malloc(sizeof(*t));
 	if (!t) return NULL;
@@ -46,6 +56,13 @@
 	t->list = NULL;
 	t->total_alloc_size = 0;
 
+// Maybe there is a way to calculate the alligned size of this structure 
+// at compile time
+
+	l=sizeof(struct talloc_chunk);
+	for(tc_offset=0;l>=0; tc_offset+=TALLOC_NEW_ALLIGN)
+		l-=TALLOC_NEW_ALLIGN;
+
 	return t;
 }
 
@@ -57,15 +74,12 @@
 
 	if (size == 0) return NULL;
 
-	p = malloc(size);
-	if (!p) return p;
-
-	tc = malloc(sizeof(*tc));
-	if (!tc) {
-		free(p);
+	tc = malloc(tc_offset+size);
+	if (!tc)
 		return NULL;
-	}
 
+	p=(void *)tc;
+	p+=tc_offset;
 	tc->ptr = p;
 	tc->size = size;
 	tc->next = t->list;
@@ -78,7 +92,8 @@
 /* a talloc version of realloc */
 void *talloc_realloc(TALLOC_CTX *t, void *ptr, size_t size)
 {
-	struct talloc_chunk *tc;
+	struct talloc_chunk *tc, *prev,*next;
+	void *p;
 
 	/* size zero is equivalent to free() */
 	if (size == 0)
@@ -88,16 +103,37 @@
 	if (ptr == NULL)
 		return talloc(t, size);
 
+	prev=NULL;
 	for (tc=t->list; tc; tc=tc->next) {
 		if (tc->ptr == ptr) {
-			ptr = realloc(ptr, size);
+			next=tc->next;
+			ptr = realloc(tc, size+tc_offset);
 			if (ptr) {
+				tc=ptr;
+				p=(void *)tc;
+				p+=tc_offset;
+				tc->ptr = p;
 				t->total_alloc_size += (size - tc->size);
 				tc->size = size;
-				tc->ptr = ptr;
+
+				if(prev) {
+					prev->next=tc;
+				} else	{
+					t->list=tc;
+				}
+				ptr=p;
+			} else {
+				if(prev) {
+					prev->next=next;
+				} else	{
+					t->list=next;
+				}
+			// should I free the data pointed by original tc ?
+                        // If I don't I am buggy but consistent with the 
rest of samba ;)
 			}
 			return ptr;
 		}
+		prev=tc;
 	}
 	return NULL;
 }
@@ -112,7 +148,6 @@
 
 	while (t->list) {
 		c = t->list->next;
-		if (t->list->ptr) free(t->list->ptr);
 		free(t->list);
 		t->list = c;
 	}
@@ -155,7 +190,8 @@
 
 	if (!newp)
 		return 0;
-
+// BUG !?! What if size is bigger then the original size ??
+// p will go over the boundary and may crash
 	memcpy(newp, p, size);
 
 	return newp;